DOI: 10.7860/JCDR/2013/5100.3115 Original Article Foramen of Civinini: A New Anatomical Guide for Maxillofacial Surgeons Anatomy Section R SHARMILA SARAN, K SUBA ANANTHI, ARUNA SUBRAMANIAM, MS THOTAKURA BALAJI, D VINAITHA, G VAITHIANATHAN ABSTRACT of lateral pterygoid plate were measured. Using X–rays the Introduction: Study on Morphometric and radiological aspect radiological view was determined. on existence of foramen of civinini. Sphenoid bone comprises Results: In this study from 160 cases of skull and sphenoid of some rare ossified ligaments, may encounter difficulty in bones revealed that complete and incomplete foramen of civinini surgical procedures. Incidence of Pterygospinous bars various in 1.25% and 7.5% of cases respectively. Peculiarly accessory with different racial groups and they are genetically controlled. foramen of civinini noticed in 1.25% of cases. Maximum area of Complete ossification of pterygospinous ligament form foramen foramen of civinini was 94.2mm2. The maximum width of lateral of civinini. Entrapments of vessels or nerves may occur due to pterygoid was noted as 19.6mm respectively. Mentocoronal existence of pterygospinous bar. The bar may locate medially view of skiagram clearly shows the bar. or inferiorly to formen ovale as seen in Hawaiian and lemurs. Conclusion: During Anaesthesia for trigeminal neuralgia may Co–existence of bar with the wide lateral pterygoid plate encounter difficult to pass the needle. The bar compress the exhibits development of the bar from herbivore, carnivore and mandibular nerve branches can cause lingual numbness, old world monkeys. Comparatively absence or small spine of pain and speech impairment. Conductive anaesthesia on the civinini noted in new world monkeys, rodents and platyrrhines. mandibular nerve through the lateral subzygomatic route may Pterygospinousbar represents the phylogenetic remnant of be difficult to approach. Exploring the anatomical and clinical Human beings. updates of pterygospinous bar may guide the surgeons and Material and Methods: By using digital vernier caliper, the radiologists to overcome any difficulties in infratemporal and measurements of length, width of the pterygospinous bar and para or retropharyngeal regions. area of foramen of civinini including the length and breadth Key words: Pterygospinous bar, Ossification, Radiology, Mandibular nerve entrapment, Phylogeny INTRODUCTION Pterygospinous bar completely differs from the pterygoalar bar The infratemporal fossa is a surgically significant region, in which because of its attachments. Pterygoalar ligament extends from the osseous part of pterygoid process extends vertically downwards root of lateral pterygoid plate to the infratemporal surface of greater from the junction of the root of greater wing and body of sphenoid. wing of sphenoid. A complete foramen which is called porus Each pterygoid process comprises of a lateral and a medial crotaphitico-buccinatorius is formed from the complete ossification pterygoid plate. The lateral pterygoid plate consists of anterior and of pterygoalar ligament [2,3]. On the basis of attachments and posterior margins. The free anterior margin forms the posterior passage of ligaments, either medial or lateral to foramen spinousm boundary of pterygomaxillary fissure. The posterior free margin or ovale [4,5], serves to distinguish pterygospinous bar. presents a small spur at the root or in the centre, which is called spine of civinini. Thickening of fascia between the lateral and MatERIAL AND METHODS medial pterygoid muscles leads to the formation of Pterygospinous A total number 160 cases of unknown age and sex which ligament, which extends from the bony spur to spine of sphenoid. consisted of 50 dried skulls and 30 dried sphenoid bones of The ligament may ossify or calcify to form pterygospinous bar. both the sides, were studied for the presence of Pterygospinous The ossification may be complete or incomplete. The complete bar. Measurements were taken by using a sliding digital vernier ossification of the bar results in an individual foramen which caliper. X–rays were used as a tool in order to determine the view is called Foramen of civinini. This foramen is completed by an of foramen. upward continuation of the interpterygoid fascia or aponeurosis, which is called cribiform fascia. This fascia is pierced by accessory RESULTS meningeal artery, nerve to medial pterygoid and tensor velli palatine A bilateral incomplete foramen of civinini was noticed in three (6 muscle. Sometimes, pterygoid venous plexus may pass through cases) bones and a unilateral incomplete foramen of civinini was the pterygospinous ligament [1]. So, ossification of ligament may observed in four cases of bones, of which three were left sided entrap the neurovascular structures and this may be an obstacle and one was a right sided bone. Particularly, one of the skulls for the mandibular nerve block. An incomplete foramen exists showed a right sided incomplete formen, a complete left sided one because of partial ossification of ligaments. and an accessory foramen of civinini [Table/Fig-1]. An individual sphenoid bone showed a unilateral complete foramen of civinini Journal of Clinical and Diagnostic Research. 2013 Jul, Vol-7(7): 1271-1275 1271 R Sharmila Saran et al., Anatomical Study on Foramen of Civinini www.jcdr.net on the right side and an incomplete foramen on the left side and it spine of civinini. The sheet may be ossified around the perforated also represented the absence of foramen spinosum on right side branches of mandibular nerve, resulting in one very small complete [Table/Fig- 2]. As a result, the complete ossified bar that formed foramen and one accessory foramen of civinini in 0.625% of the a complete foramen of civinini was noticed in two (1.25%) cases, cases. one on left side of the skull and other on right of the sphenoid bone. In both the cases, pterygospinous bar was placed across or inferiorly to the foramen ovale [Table/Fig-1 and 3] [6-9]. Incomplete foramen of civinini were noticed in 12 (7.5%) cases. The peculiar sphenoid and a skull bone which showed a larger area and accessory foramen of civinini were considered, to be discussed. In a sphenoid bone, the maximum width of lateral pterygoid plate which was measured at the level of spine of civinini and root was approximately 19.6mm and 17mm and the length was 12mm and area of foramen of civinini in a sphenoid bone was 94.2mm2. The transverse and vertical diameters were 10mm and 12mm [Table/ Fig-4]. The length and width of the pterygospinous bar were 12mm and 3.5mm respectively. The same sphenoid bone also showed [Table/Fig-3]: Basal view PSB inferiority across the foramen ovale complete ossification of carotico–clinoid and interclinoid ligament, a - Foramen ovale; b - Foramen spinosum; which was significant. On left sided skull bone, it was difficult to c- Absence of foramen spinosum; * - Pterygospinous bar measure the length and width of pterygospinous bar and area of foramen, because the pterygospinous bar was not present in a single stretch, from one point to other. Rather, pterygospinous ligament may spread as a thin sheet from spine of sphenoid to [Table/Fig-1]: Basal new - Left side complete & accessory foramen. [Table/Fig-4]: Lateral view, sphenoid bone with large area of foramen Right side3 foramen of civinini (right side) a - Lateral pterygoid plate; b - Medial pterygoid plate; a - Lateral pterygoid; al - Spine of civinini; b - Spine of sphenoid. c - Spine of sphenoid (right side) * - Pterygospinous bar; Arrow shows large area of foramen of civinini cl - Spine of sphenoid (illdefined left side); A - Foramen of civiaini Al - Accessory foramen of civinini, * - Spine of civivnini Arrow shows incomplete Foramen of civinini [Table/Fig-2]: Poserior view - sphenoid bone exhibits incomplete foramen of leftside and complete foramen on right side a - Lateral pterygoid plate, b - Medial pterygoid plate, [Table/Fig-5]: Skiagrtam - Basal view * - Pterygospinous bar a - complete foramen of civini; b - Incomplete foramen of civinini Arrow shows foramen of civinini Basal view clearly shows pterygospinous bar on left side 1272 Journal of Clinical and Diagnostic Research. 2013 Jul, Vol-7(7): 1271-1275 www.jcdr.net R Sharmila Saran et al., Anatomical Study on Foramen of Civinini DISCUSSION foramen couldn’t be found [17], but in contrary, pterygospinous The thickened cranial part of fascia, between the lateral and medial bar was observed in the skulls of younger individuals [10,11]. pterygoid muscles, results in fibrous bands which are named as Ps foramen was found in 5.46% of 2,745 skulls of American pterygospinous ligaments. Italian anatomist F Civinini (1805-1844), and Negroes and it was more frequent in whites [7]. Among 312 first described and coined the term “pterygospinous ligament” or dry human skulls from major Brazilians, Ivan et al., classified the “ligament of civinini, but earlier, Pterygospinous bar used to be complete and incomplete ossification of pterygospinous ligament named as ala Ingrassiae, after its invertor GF Ingrassia (1510-1580), as types 1 (1.6%) and 2 and notified that the maximum diameter who is also known as “Hippocrates of Sicily”. Ossified ligament of the foramen of civinini was 10.626mm [18]. Group of basal projects as a bar, medial or lateral or sometimes across the foramen cranial studies for the presence of pterygospinous bar from various ovale in the submento vertical projection and it may interfere with regions like Europe, North pacific coast and Japan projected 4.5%, percutaneous injection of the mandibular nerve. Pterygospinous 5.9% and 4% [19, 20]. Complete ossification of pterygospinous bar passed medial to foramen spinosum and crossed the foramen bar was found to be 3-4% in the skulls of sociopaths and criminals ovale at an angle of 20º – 40º degree to the sagittal plane [9]. In the [21], to be 2-7% in Caucasians and to be 12-13% in African skulls present report, the complete pterygospinous bar was parallel across [22]. On considering the number of bones or cadavers, prevalence the foramen ovale, with the absence of foramen spinosum in an and incidence outcomes from the study were found to vary with individual sphenoid bone.